Fusion 360 to 3D Printer —
In 3 Steps, Zero Uploads

Why Fusion 360 Users Need a Local Converter

Fusion 360 is the tool of choice for millions of mechanical engineers, product designers, and serious hobbyists. It's powerful, parametric, and exports clean STEP files. But when it comes time to 3D print, most people run into the same wall: they need a mesh format (STL, OBJ, or 3MF) and Fusion's built-in STL export, while functional, doesn't always produce the cleanest result for complex assemblies.

The usual answer is an online converter. The problem: those converters upload your file to a server. Your geometry, tolerances, and design intent leave your machine. If you work on anything proprietary — a client project, a patent-pending design, a product in development — that's an IP leak.

Step 1 — Export STEP from Fusion 360

Fusion 360 has excellent STEP export. Here's the exact workflow:

1. Complete your design and check visibility

   Make sure all the bodies and components you want to print are visible. Hidden components won't be included in the export.

2. File → Export → STEP Files (*.step, *.stp)

   In the export dialog, choose STEP format. Both AP203 and AP214 work fine with Simpel3D. AP214 preserves colour metadata if that matters to you.

3. Save to your local machine — not Fusion's cloud

   Critical: choose a local save path. This ensures the file exists only on your device before conversion.

Step 2 — Convert Locally with Simpel3D

Open simpel3d.com and drag your STEP file onto the drop zone. No account, no email, no upload. The file is processed entirely within your browser using the OpenCASCADE WASM engine — the same geometric kernel used in professional CAD software.

Select your output format:

• STL — works with every slicer ever made. Use this when in doubt.
• 3MF — better for Bambu Studio, PrusaSlicer, Cura 5+. Carries unit and scale information that STL doesn't.
• OBJ — use this if you need vertex normals for rendering, or you're passing the file to Blender.

Step 3 — Open in Your Slicer

Download the converted file and open it in your slicer. For Bambu Studio: drag directly onto the build plate. For Cura: File → Open File. For PrusaSlicer: drag and drop or Ctrl+I.

Handling Multi-Part Assemblies

If your Fusion 360 design is a multi-component assembly — a housing with a lid, a joint with multiple bodies, a mechanism with several parts — you have two options:

Option A: Convert the whole assembly to a single mesh

Simpel3D merges all components into one mesh. Good for simple assemblies where you want everything in one file. Not ideal for multi-material printing.

Option B: Use the Assembly Splitter

For assemblies above ~60MB, or when you want individual files per component, Simpel3D automatically activates the Assembly Splitter — it processes each component separately and delivers a ZIP of individual STL/OBJ/3MF files, named using the original component names from your Fusion 360 design tree.

What About Fusion's Native STL Export?

Fusion 360 does have a built-in STL export. So why use a converter? A few reasons:

• Tessellation quality: Simpel3D lets you control the deflection parameters that determine how precisely curves are approximated by triangles. Fusion's default STL export sometimes produces coarser meshes than needed.
• 3MF output: Fusion's 3MF export has historically been inconsistent. Converting via STEP → Simpel3D → 3MF tends to produce cleaner output for modern slicers.
• Assembly handling: For complex assemblies, exporting from STEP through a WASM-based converter gives more control over how components are merged or split.